The present invention relates to an insulating system for metal buildings and, in particular, to such a system which is suspended from the ceiling of metal buildings.
Various methods and systems have been developed to insulate the ceilings or roof structure of corrugated sheet metal. The roof structure of most metal buildings comprises metal sheets supported on a support structure of cross-members or purlins running the length of the building which are in turn supported on spaced, rib-like I-beams or main support beams.
One common practice is to insulate a metal building during construction by installing blankets or strips of insulation on top of the cross-members prior to installing the final layer of sheet metal forming the roof. This practice interferes with the completion of the building itself and leaves the lower and inside support structure of the roof exposed. Leaving the support structure of the roof exposed results in the main support beams extending about one foot below the ceiling. Such extension by the main beams increases maintenance costs, because cleaning is required, and results in a very uneven surface that is difficult to light, because the main beams block and prevent dispersion of light reflected off the ceiling. The compression of the insulation between the cross-members and metal sheets forming the roof also reduces the efficiency of the insulation.
U.S. Pat. No. 4,391,075 discloses an insulation system particularly adapted for insulating metal buildings having pitched roofs. In the system disclosed in U.S. Pat. No. 4,391,075, blankets of insulation are supported against the lower surface of the purlins of the roof structure by a system of tubes suspended from the purlins. The tubes are suspended from the purlins so as to extend parallel thereto between adjacent support beams such that the support beams extend substantially below the insulation supported on the tubes. The extension of the support beams below the insulation results in increased maintenance costs and in an uneven surface that is difficult to light. The exposed support beams also serve as direct heating and cooling conductors that bypass the insulation.
Historically, there has been a reluctance to construct buildings of this type, with any space between the sheet metal, the insulation and the inner ceiling, due to collection of vapor condensation within such a space and resulting problems. Further, historically, such a space was not ventilated to reduce vapor condensation because the prior art ceilings were not airtight and ventilation would draw too much heated or cooled air from the building, thereby rendering the insulation ineffective. In particular, practice in using conventional insulation systems is shown in U.S. Pat. No. 4,391,075 which teaches the elimination of the airspace between the blankets of insulation supported on the tubes and the metal sheets of the roof by the insertion of additional insulation therebetween. The airspace is eliminated to reduce the likelihood of water vapor condensing therein.